1. Field of the Invention
This invention generally relates to ligating instruments and more particularly to instruments capable of dispensing ligating bands in a sequential manner.
2. Description of Related Art
The treatment of various types of lesions including internal hemorrhoids by ligation is well known. The object of ligation is to position an elastic cord, or ligating band, at the lesion to stop circulation through tissue and allow the tissue to die whereupon the body sloughs off the dead tissue. When lesions are located deep in the alimentary tract, physicians generally use either band ligation or sclerotherapy. However, they prefer to make that selection after viewing the lesion endoscopically. With prior art devices, a physician must then select either band ligation or sclerotherapy apparatus for insertion through a working channel of the endoscope.
The following patents disclose various embodiments of ligating band dispensing instruments and apparatus useful for sclerotherapy:
3,760,810 (1973) Van Hoorn PA1 4,222,380 (1980) Terayama PA1 4,257,419 (1981) Goltner et al PA1 4,735,194 (1988) Stiegmann
U.S. Pat. No. 3,760,810 to Van Hoorn discloses an instrument for facilitating the placement of a single ligating band or set of bands. The instrument includes, at its distal end, a ligating band dispenser comprising two rigid, concentric tubes. The tubes can slide with respect to each other under the control of a trigger mechanism at the proximal end of the instrument. A rigid endoscope having internal passages forming a suction path and a light path interconnect the trigger mechanism and dispenser. The inner tube can be loaded with a set of one or more elastic rings or ligating bands. A separate stopper bar attaches to the instrument to prevent premature dispensing. When the instrument is located proximate a lesion, a physician removes the stopper bar and applies vacuum to draw tissue into a hollow passage at the distal end of the instrument. Pulling on the trigger retracts the inner tube. A radial surface or shoulder on the outer tube engages the ligating band so it can not displace with the inner tube. As the inner tube is withdrawn from the ligating band, it collapses onto the tissue.
U.S. Pat. No. 4,222,380 to Terayama discloses apparatus adapted for sclerotherapy in the form of a celiac injector for injecting a medical fluid into desired celiac tissue. In the specifically disclosed apparatus a medical fluid supply tube with an injector needle fixed at its tip end thereof and an elongated member fitted at its tip end with a plurality of claw wire elements are relatively slidably housed in an outer sheath. By manual operations of the respective proximal end portions of the supply tube and elongated member, the claw wire elements take hold of a tissue portion at a desired part, the needle is stabbed into the held tissue portion, and the medical fluid supplied through the supply tube is injected into the tissue by means of the injector needle.
U.S. Pat. No. 4,257,419 to Goltner et al discloses a rigid endoscope that includes a ligating band dispenser with an inner tube that moves with respect to an outer tube to dispense a ligating band. This dispenser is oriented at right angles to the rigid endoscope and includes a structure for moving the inner tube of the dispenser in this configuration.
U.S. Pat. No. 4,735,194 to Stiegmann discloses a flexible endoscope ligating instrument in which a flexible endoscope structure includes a biopsy channel and a suction channel extending between the proximal and distal ends. A dispenser, like the dispenser structure shown in the Van Hoorn and Goltner patents, includes an inner tube that moves axially with respect to an outer tube at the distal end of the instrument. The outer tube connects to the distal end of the endoscope. An operating mechanism in the form of a pull wire with a weighted handle maintains tension on the inner tube so it does not displace axially outward while the instrument is being positioned. For some applications it is suggested that the endoscope structure be inserted through an overtube to prevent premature dispensing. Suction can be applied to draw tissue into a central aperture of the dispenser. Then a physician pulls the handle and retracts the inner tube axially past the distal end of the outer tube to force the ligating band off the instrument onto the tissue.
Each of the instruments disclosed in the Van Hoorn, Goltner and Stiegmann patents dispenses a single ligating band or a single set of ligating bands at a single location. None of the patents suggests dispensing ligating bands at discrete locations. The Van Hoorn patent does disclose the possibility of depositing plural ligating bands. However, Van Hoorn seems only to suggest dispensing plural ligating bands at a single site in a single operation. The apparatus disclosed in the Van Hoorn, Goltner or Stiegmann patents apparently would have to rely on a physician's sense of touch in order to displace the inner tube by an incremental distance corresponding to the thickness of a stretched ligating band to deposit a plurality of bands at different sites. That would be very difficult to accomplish.
Indeed, when it is desired to deposit ligating bands at different sites, the common practice is to withdraw the entire instrument from the patient and load a new ligating band onto the inner tube. Loading ligating bands on an instrument requires special tools and can be time consuming particularly if the special tooling must be retrieved to install each ligating band individually while the instrument is withdrawn. Each of these instruments requires some structure, such as special stoppers or overtubes, for preventing the premature dispensing of the ligating band. Consequently, none of these instruments is readily adapted for dispensing ligating bands at different sites without withdrawing the instrument after each individual site is ligated.
Each of the instruments in the Van Hoorn, Goltner and Stiegmann patents also is dedicated to band ligation therapy. There is no suggestion that this apparatus can or should be combined with any other apparatus for performing any other procedure such as sclerotherapy. Similarly the Terayama patent discloses apparatus that is dedicated to celiac injection. There is no suggestion that this apparatus can or should be combined with any other apparatus for performing any other procedure, such as band ligation.
In current practice a physician normally begins therapy by visualizing some or all of the lesions with an endoscope to establish a therapy plan. Then the physician withdraws the endoscope to add either a ligating band dispenser or sclerotherapy apparatus. Next, the physician reinserts the endoscope to perform the desired therapy. If the physician decides on a different therapy for a subsequent lesion or the use of both sclerotherapy and ligating band therapy on a single lesion, the physician withdraws the endoscope, changes the apparatus and reintroduces the modified endoscope. This withdrawal and replacement procedure will be required if successive lesions are to be treated alternately by band ligation or if successive lesions are to be treated by band ligation and sclerotherapy. It is only when successive lesions are to be treated by sclerotherapy that the withdrawal replacement procedure is avoided. As will be apparent, these procedures complicate the physician's work and prolong the time required to treat the lesions.